These are some of the gemstones that I usually have for sale.
I can’t offer investment advice. I can say that I am buying ALL the Mali Garnets I can
 Mali Garnets are becoming much harder to find, especially the yellows. Spinels I am buying because they are a beautiful gem and not well known, once they appear on the Shopping Channel, everyone will want them. The same thing happened years ago with Morganite, no one had heard of it then everyone wanted it and the prices shot up.
Also Red and Blue Spinels.
I also sometimes have small Argyle Pink Diamonds. The price has shot up over recent years. There are no more being mined. If you are going to buy them, make sure they have a Certificate from a Registered Valuer that traces the Diamond back to its original tender/lot number, otherwise they are worth 30-50% less!

Red Amber

Amber is fossilised tree resin. Most people are familiar with Baltic Amber from Europe, but fine red Amber is found in Burma. Many of the pieces from Burma contain fossils, mainly ants and small flying insects.

PERIDOT

Pakistan is known for its Peridot, but Vietnam has larger and better coloured gems. Gems up to 20cts are not uncommon and they also find beautiful crystals in the original Basalt.

AQUAMARINE

Some of the best coloured Aquamarine comes from Vietnam and again large gems can be found. It is very hard to find eye clean gems larger than 5cts, but the inclusions often add to the character of th gem and always let you know that they are real.

HELIODOR.

This is the lesser known sister of Aquamarine and Emerald, but every bit as beautiful. The colour is a beautiful deep yellow and larger gems up to 15cts are available. They make stunning pendants.
Here are some we purchased in Vietnam

ZULTANITE.

This is a ‘rare’ gemstone found in Turkey. It is also found in Russia, where it is known as ALEXANDRITE. The difference is price! Alexandrite costs thousands of dollars per carat, whereas Zultanite costs hundreds. Incandescent light shows the gem change colour from green to red and the greater the change, the more valuable the gem.
MALI GARNET
The yellow coloured garnets sparkle almost like diamonds. They are becoming more difficult to obtain as the supply from Africa is drying up. If you asked me what gem to buy for investment I would say either Mali Garnet or Argyle Pink Diamond. If you can find a good yellow over 3cts my advice to me would be to buy it.
SPESSARTINE GARNET.
Spessartines come in yellows, through orange to red. Be careful though as some of the gems have a ‘brown’ undertone that deflates the colour. ‘Fanta’ orange is the colour most sought after however the reds have a fire and passion to them.
SPINEL.
This and Zircon are the two most underrated gemstones. We think of Spinel (aka black jack) as a black waste product of Sapphire mining. For many years in Thailand this was also the case. Thai Black Spinel can be as large as your fist. It takes a beautiful polish and well cut makes spectacular men and womens rings.
Spinel also comes in all colours with the exception of pure yellow or green. Red from Burma are highly prized and priced accordingly. However the most rare and prized is the Cobalt Blue. Found only in Tanzania and Luc Yen in Vietnam it is really a collectors gem. Gems over 1ct are super rare and command tens of thousands of dollars US per ct.
EMERALD.
I prefer Emeralds from Russia, even though these days people may find it politically on the nose. I bought Russian because they have beautiful coloured, quite clear gemstones. Columbian Emeralds of the same quality cost thousands of dollars per carat, instead of hundreds per carat. This means you can buy a larger, more beautiful gemstone.
RUBY.
I have Vietnamese Ruby as these are more reasonably priced than Burmese gems. They tend to be more pinkish than their Vietnamese cousins. I can source any size and colour Ruby that you want. Currently a good quality Burmese Ruby of 1ct will cost about $12 500. Thailand has some spectacular pink Sapphires with great depth of colour and very reasonable price.
DIAMONDS.
I usually have a few small Diamonds up to about 0.5cts. Diamonds really are a specialist field, so I only keep a few on hand. When I need larger or better quality diamonds, I use a really good Broker based in Bangkok. Because Diamonds can be described EXACTLY, it is easier to buy them than a harder to describe gemstone like a Sapphire. Colour Grading of Diamonds is definitely a skill and I use a Brisbane based Valuer who is very experienced and can Certify your Diamond.